The reduction of structure-borne road noise by active noise and vibration control

Abstract

In this work, the feasibility of active structural and acoustic control of structure-borne rolling noise in a passenger car is demonstrated. A full vibroacoustical analysis of the demonstrator vehicle was carried out, in order to characterize fully the on-road behavior (coherence analysis, operational force analysis, and transfer path analysis), as well as to derive the necessary input/output models. The results of these analyses have been used as input for the actuator design and the control configuration determination (reference signals, actuator number and location, feedback signal determination). Different control configurations have been investigated and tested by means of numerical simulations and laboratory tests. Two control configurations, each using a different kind of control source, have been retained: a structural acoustic control system which works with six inertial shakers positioned at the main vibration transmission paths of the car suspension, and an antinoise system with four loudspeakers inside the cabin. A new inertial actuator based on the moving coil work principle has been designed and realized. A broadband control system based on an adaptive feedforward control system using six reference signals, 6/4 actuators (ASAC/ANC), and four error signals has been implemented and tested in the demonstrator car.